Pasteurella bettyae Infections in Men Who Have Sex with Men, France

Pasteurella bettyae is a gram-negative bacillus sporadically involved in human infections; its main reservoirs are cats and dogs. A recent publication suggests the possibility of sexual transmission leading to genital infections in men who have sex with men. We report 9 cases in France of genital infection among this population.

One patient had a cat, another acknowledged contact with cows 2 weeks before clinical signs appeared, and 2 reported no contact with animals; data were missing for the other 4 patients.The main clinical manifestations were balanitis (4/9, 44.4%) and balanoposthitis (2/9, 22.2%).Balano-preputial sulcus ulcers in 2 patients were ultimately diagnosed as lymphogranuloma venereum and syphilis and urethral discharge in 1 patient was diagnosed as gonorrhea.No other signs or symptoms, including fever or lymphadenopathy, were reported (Table 1).
According to national guidelines, we presumptively treated patients with antimicrobial drugs; those with ulcers received benzathine benzylpenicillin plus doxycycline and the patient with urethral discharge received ceftriaxone plus doxycycline.We targeted co-pathogens when detected by nucleic acid amplification tests.One patient who had not received antimicrobial drugs attended a review visit and recovered after receiving specific treatment (cefixime) (Table 1).
We obtained P. bettyae colonies after 24-hour culture on polyvitex agar (bioMérieux, https://www.biomerieux.com) at <5% CO 2 and 35°C-37°C.We identified P. bettyae using Vitek MS matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (bioMérieux).We used disk diffusion (Bio-Rad Laboratories, https://www.bio-rad.com)on polyvitex agar to test antimicrobial susceptibility and interpreted results according to European Committee on Antimicrobial Susceptibility Testing recommendations (5).All P. bettyae isolates showed susceptibility to amoxicillin/clavulanic acid, ceftriaxone, tetracycline, and fluoroquinolones, as is usually observed for this genus.One isolate from patient 9 exhibited resistance to amoxicillin and penicillin G (penicillin G MIC of 0.75 mg/L), 1 from patient 4 to penicillin G only, and 1 from patient 8 to trimethoprim/sulfamethoxazole (Table 1).
We performed whole-genome sequencing and bioinformatics analysis of 6/9 available P. bettyae isolates (BioProject accession no.PRJNA1039245) as described elsewhere (6).We developed the distance matrix of Pasteurella clinical isolates and rooted it by comparison with the genome reference sequence of P. bettyae strain CCUG 2042 (National Center for Biotechnology Information Reference Sequence database accession no.NZ_AJSX01000007.1).We observed relatedness between all P. bettyae isolates (Table 2), highlighting that 4 isolates, from patients 1, 3, 5, and 6, were closely related, varying among them by only 12-270 single-nucleotide polymorphisms and by 587-628 SNPs from the P. bettyae CCUG 2042 strain described in 2012 in the United States.Isolates from patients 4 and 7 were more distant but had ribosomal identification and 16S rRNA of P. bettyae.
The 9 cases of genital P. bettyae infection exclusively in MSM we describe clustered within a 4-year period; no case was registered at our hospital before 2018.Fewer than 50 cases (mainly genital) have been reported worldwide across the previous 60 years, in male and female patients.In this series, the most specific clinical manifestation was balanitis/balanoposthitis. Because only 1 patient received targeted treatment, we could not deduce that P. bettyae was solely responsible for his symptoms or treatment responsible for his recovery.In case-patients with ulcers and urethritis, P. bettyae superinfection was more likely.Only half of patients for whom information was available had contact with animals, which provides insufficient support to determine direct anthropozoonotic transmission.Two thirds of patients reported not using condoms and the remaining third not using them for oral sex, which is not enough evidence to determine the transmission route and preventive efficacy of using condoms.However, if balanitis is indeed the main clinical manifestation, condoms provide an obvious physical barrier.Of note, the first case in this cluster occurred 2 years after PrEP policy implementation in France, but  whether receding usage of condoms by PrEP users had any part in this emergence remains speculative.P. bettyae appears to be an emerging cause of sexually transmitted genital infection among MSM in Europe (3).More case descriptions are needed to delineate its clinical spectrum and appropriate handling.We encourage physicians to test bacterial swab samples when managing similar genital symptoms, especially balanitis.

About the Author
Mr. Li is a medical resident at Hôpital Saint-Louis Centre for Genital and Sexually Transmitted Diseases, Paris, France, specializing in dermatology and venereology.
P lasmodium vivax, the most widely geographi- cally distributed species of the Plasmodium genus, causes malaria in humans and is transmitted through the bite of infectious Anopheles mosquitoes.P. vivax is the second most prevalent cause of malaria globally and constitutes a large portion of the annual malaria cases in the Western Hemisphere; ≈397,000 cases of P. vivax malaria were reported in the Americas in 2022 (1).Conversely, P. vivax malaria is relatively infrequently encountered at most institutions in the United States because most cases are travel-associated.The Centers for Disease Control and Prevention (CDC) reported 72% of all P. vivax cases in the United States in 2018 were imported from malaria-endemic countries (2).A central epidemiologic factor of P. vivax is its ability to establish a dormant liver stage that can later reactivate, leading to episodic parasitemia.This latent stage poses a potential risk for transmission to another human through a mosquito vector if appropriate treatment is not administered (3).
Since early 2023, Los Angeles General Medical Center in Los Angeles, California, USA, has observed a concerning rise in P. vivax cases, specifically among immigrants from China entering the United States via the southern US border.We diagnosed 10 cases of P. vivax malaria, 9 of which were among immigrants from China who came to the United States by land via South and Central America.In contrast, we only saw 2 cases of P. vivax at our institution during 2016-2022, one patient in 2017 and another in 2018, neither of whom were of

Table 1 .
Demographic and behavioral characteristics, bacteriological data, clinical manifestations, and evolution of Pasteurella bettyae infection among 9 men who have sex with men, France* 1476 Emerging Infectious Diseases • www.cdc.gov/eid• Vol. 30, No. 7, July 2024 RESEARCH LETTERS

Table 2 .
Differences in single-nucleotide polymorphisms among 6 Pasteurella bettyae isolates from 9 men who have sex with men,